<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <script>
      class Person {
        static username = "jack";
        username = "lili"; //this.username
        static say() {}
        say() {} // this.say
      }
      class Admin extends Person {
        // constructor(){
        //   return this
        // }
      }
      console.log(Admin.username);

      // const p = new Person();
      const a = new Admin();
    </script>
  </body>
</html>
